Diaphragm-sealed valve having a locking mechanism

ABSTRACT

A valve includes a valve cap, a valve body, a diaphragm, biasing means and a locking mechanism. The valve cap includes a plurality of process conduits and process ports. The valve body faces the valve cap and includes a plurality of plunger passages extending therein. The diaphragm is positioned between the valve cap and the valve body. The valve body includes a plunger assembly, a first support structure and a second support structure. The plunger assembly includes a plurality of plungers, each slidable between a closed position and an open position. In the closed position, the plunger deforms the diaphragm in order to block communication between two of the process ports. In the open position, the plunger is retracted away from the diaphragm. Each plunger is either a normally closed plunger or a normally open plunger. The normally closed plungers are mounted upon first support structure and the normally open plungers are mounted upon the second support structure. The locking mechanism is for engaging the first support structure and thereby physically restraining the normally closed plungers in the open position. A valve body assembly is also described.

FIELD OF THE INVENTION

The present invention generally relates to fluid analytical systems andmore particularly concerns a valve and a valve body assembly having alocking mechanism.

BACKGROUND OF THE INVENTION

As well known by people involved in the art, chromatographic systemsrely on the use of valves to allow reproducible sample introduction andvarious column switching schemes.

For the last forty years, many people have designed diaphragm valves forchromatography. Such diaphragm valves have been used in manycommercially available gas chromatographs. They are apt to be integratedmore easily in a gas chromatograph due to their physical size and sincethe actuator is embedded in the valve itself. These characteristics makethem attractive for gas chromatograph manufacturers.

For example, international application no. PCT/CA2008/002138, filed Dec.5, 2008 by the present applicants and published as WO2009/073966,discloses such a diaphragm-sealed valve. In addition, U.S. Pat. Nos.7,216,528 and 7,503,203 issued to the present applicants May 15, 2007and Mar. 17, 2009, respectively, discloses other types ofdiaphragm-sealed valves.

Referring now to FIG. 1 (PRIOR ART), there is shown an example of atypical diaphragm-sealed valve as known in the art. The valve 1 isprovided with a top block 2 having an interface 4 and a plurality ofports 6. Each of the ports 6 opens at the interface 4 and has aninclined thread passage 8 to connect various analytical fitting andtubing (not shown). At the bottom of the inclined thread passage 8,there is a conduit 10 extending in the top block 2 and opening at theinterface 4. The ports 6 are arranged on a circular line on theinterface 4 of the top block 2. The interface 4 is advantageously flatand polished to minimize leaks between ports and from the ambientatmosphere. The valve 1 is also provided with a bottom block 12 and adiaphragm 14, which is generally made of polyimide, Teflon or otherpolymer material. The diaphragm 14 is positioned between the top blockinterface 4 and the bottom block 12, and has a recess 18 thereinextending along the circular line formed by the ports 6 and biased awayfrom the interface 4 of the top block 2. The recess 18 in the diaphragm14 sits in a matching recess 20 made in the bottom block 12, therebyallowing some clearance for fluid circulation between adjacent ports 6.

The valve 1 is also provided with a plurality of plungers 16 mounted inthe bottom block 12, each being respectively arranged to be able tocompress the diaphragm 14 against the top block 2 at a position locatedbetween two of the ports 6. Preferably, as illustrated, when the valveis at rest, three plungers 16 are up while the other three are down.When the plungers are up, they compress the diaphragm 14 against the topblock 2 and close the conduits made by the diaphragm recess 18, so thatfluid circulation is blocked. The bottom block 12 keeps the plungers 16and the actuating mechanism in position.

It is common to designate a portion of the plungers 16 as “normallyopen” and another portion as “normally closed”. A normally open plunger16 is biased downwards, i.e. away from the diaphragm 14, and thereforenormally allows fluid circulation between the two adjacent ports 6. Anormally closed plunger 16 is biased upwards, i.e. towards the diaphragm14, and therefore blocks fluid circulation between the two adjacentports 6. A user may actuate the valve 1 in order to alter the positionsof the plungers 16, for example by sliding upwards and downwards thenormally open and closed plungers 16, respectively.

However, it has been found that prolonged deformation of a diaphragm bya normally closed plunger, for example during storage or shipping, candamage the diaphragm. This damage can both shortens the diaphragm's lifeand compromise the system's performance. A damaged diaphragm can alsoincrease the leak rate from port to port. When the pressure drop on thevalve's ports differs from port to port, the pressure and flow may varyin the system. This causes detrimental effects on column performance anddetector baseline.

There is therefore a need for an improved diaphragm-sealed valve.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, there isprovided a valve that includes a valve cap, a valve body, a diaphragm,biasing means and a locking mechanism. The valve cap includes aplurality of process conduits extending therethrough, each of theprocess conduits ending in a process port. The valve body faces thevalve cap and includes a plurality of plunger passages extendingtherein. The diaphragm is positioned across the process ports andbetween the valve cap and the valve body. The valve body includes aplunger assembly, a first support structure and a second supportstructure. The plunger assembly includes a plurality of plungers. Eachof the plungers is positioned in a respective one of the plungerpassages and slideable therein between a closed position and an openposition. In the closed position, the plunger deforms the diaphragm inorder to block communication between two of the process ports. In theopen position, the plunger is retracted away from the diaphragm. Each ofthe plungers is either a normally closed plunger or a normally openplunger. The normally closed plungers are mounted upon first supportstructure and the normally open plungers are mounted upon the secondsupport structure. The biasing means are for biasing the normally closedplungers towards the diaphragm and biasing the normally open plungersaway from the diaphragm. The locking mechanism is for engaging the firstsupport structure and thereby physically restraining the normally closedplungers in the open position.

In accordance with a second aspect of the present invention, there isalso provided a valve body assembly for a valve. The valve includes avalve cap that includes a plurality of process conduits extendingtherethrough. Each of the process conduits ends in a process port. Thevalve further includes a diaphragm positioned across the process ports.The valve body assembly includes a valve body, a plunger assembly,biasing means and a locking mechanism. The valve body includes aplurality of plunger passages extending therein. The diaphragm ispositioned between the valve body and the valve cap. The plungerassembly includes a plurality of plungers, each of the plungers beingpositioned in a respective one of the plunger passages and slideabletherein between a closed position and an open position. In the closedposition, the plunger deforms the diaphragm in order to blockcommunication between two of the process ports. In the open position,the plunger is retracted away from the diaphragm. Each of the plungersis either a normally closed plunger or a normally open plunger. Thenormally closed plungers are mounted upon first support structure andthe normally open plungers are mounted upon the second supportstructure. The biasing means are for biasing the normally closedplungers towards the diaphragm and biasing the normally open plungersaway from the diaphragm. The locking mechanism is for engaging the firstsupport structure and thereby physically restraining the normally closedplungers in the open position.

Preferably, the locking mechanism includes a first transverse passage inthe valve body which extends perpendicular to the plunger passages, asecond transverse passage extending through the first support structurewhich is alignable with the first transverse passage when the normallyclosed plungers are in the open position, and a locking pin insertablethrough both the first and second transverse passages, therebyrestraining the normally closed plungers in the open position.

Alternatively, the locking mechanism preferably includes an extensionmounted to the first support structure and which extends through thevalve body, the extension being movable with the first support structureas the normally closed plungers slide between the open and closedpositions, and a restraining mechanism positionable between the valvebody and the extension when the normally closed plungers are in the openposition.

The locking mechanism may also alternatively include a threaded passageextending through the valve body parallel to the plunger passages, and alocking screw adapted to threadedly engage the threaded passage and bepositioned at a locking position wherein the locking screw engages thefirst support structure thereby restraining the normally closed plungersin the open position.

It will be appreciated that a valve or valve body assembly in accordancewith present invention may advantageously be used in a chromatographicsystem, or indeed in another application utilizing a diaphragm-sealedvalve.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the invention will becomeapparent upon reading the detailed description and upon referring to thedrawings in which:

FIG. 1 (PRIOR ART) is an exploded perspective view of a diaphragm-sealedvalve known in the art, in partial transparency.

FIG. 2 is an exploded perspective view of a diaphragm-sealed valve inaccordance with an embodiment of the invention.

FIG. 3 is a top view of a diaphragm-sealed valve of FIG. 2.

FIG. 4 is a cross-sectional side view of the diaphragm-sealed valve ofFIG. 3 taken along line IV-IV. FIGS. 4A, 4B and 4C are enlarged views ofsections 4A, 4B, 4C of FIG. 4. FIG. 4D is an enlarged view of section 4Dof FIG. 4C.

FIG. 5 is a cross-sectional side view of the diaphragm-sealed valve ofFIG. 3 taken along line V-V. FIG. 5A is an enlarged view of section 5Aof FIG. 5. FIG. 5B is an enlarged view of section 5B of FIG. 5.

FIG. 6 is a cross-sectional side view of the diaphragm-sealed valve ofFIG. 3 taken along line VI-VI. FIG. 6A is an enlarged view of section 6Aof FIG. 6. FIG. 6B is an enlarged view of section 6B of FIG. 6.

FIG. 7A is a top view of the valve cap of the valve of FIG. 2, accordingto a preferred embodiment of the present invention. FIG. 7B is across-sectional side view of the valve cap along line B-B of FIG. 7A.FIG. 7C is a cross-sectional view of the valve cap along the lines C-Cof FIG. 7A. FIGS. 7D and 7E are a bottom perspective view and a topperspective view of the valve cap of FIG. 7, respectively.

FIG. 8A is a top view of the valve body of the valve of FIG. 2,according to a preferred embodiment of the present invention. FIG. 8B isa cross-sectional side view of the valve body along line B-B of FIG. 8A.FIG. 8C is an enlarged view of section 8C of FIG. 8B. FIG. 8D is abottom perspective view of the valve body of

FIG. 8A. FIG. 8E is a bottom view of the valve body of FIG. 8A. FIGS. 8Fand 8G are cross-sectional side views of the valve body along line F-Fand G-G of FIG. 8E, respectively. FIG. 8H is a top perspective view ofthe valve body of FIG. 8A.

FIG. 9A is a top view of the diaphragm of the valve of FIG. 2, accordingto a preferred embodiment of the present invention. FIG. 9B is across-sectional side view of the diaphragm along line B-B of FIG. 9A.FIG. 9C is an enlarged view of section 9B of FIG. 9B. FIG. 9D is aperspective view of the diaphragm of FIG. 9A.

FIG. 10A is a top view of the push plate of the valve of FIG. 2,according to a preferred embodiment of the present invention. FIG. 10Bis a side view of the push plate of FIG. 10A, FIG. 10C is a bottom viewof the push plate of FIG. 10A while FIG. 10D is a top perspective viewof the push plate of FIG. 10A.

FIG. 11A is a bottom perspective view of the normally open piston of thevalve of FIG. 2, according to a preferred embodiment of the presentinvention, while FIG. 11B is a top perspective view of the normally openpiston of FIG. 2.

FIG. 12A is a bottom perspective view of the normally closed piston ofthe valve of FIG. 2, according to a preferred embodiment of the presentinvention, while FIG. 12B is a top perspective view of the normallyclosed piston of FIG. 2.

FIGS. 13A and 13B are a bottom perspective view and a top perspectiveview of the bottom cap of FIG. 2, respectively.

FIG. 14A is a top view of a diaphragm-sealed valve according to a firstpreferred embodiment of present invention. FIG. 14B is a cross-sectionalside view of the diaphragm-sealed valve of FIG. 14A taken along lineVI-VI. FIG. 14C is an enlarged view of section 14C of FIG. 14B.

FIG. 15A is a top view of the diaphragm-sealed valve of FIG. 14A, withlocking pins inserted. FIG. 15B is a cross-sectional side view of thediaphragm-sealed valve of FIG. 15A take along line VI-VI. FIG. 15C is anenlarged view of section 15C of FIG. 15B.

FIGS. 16A and 16B are cross-sectional views of a diaphragm-sealed valveaccording to a second preferred embodiment of the present invention.FIG. 16C is a front view a locking pin in accordance with the embodimentof FIGS. 16A and 16B.

FIGS. 17A and 17B are cross-sectional views of a diaphragm-sealed valveaccording to a third preferred embodiment of the present invention. FIG.17C is a perspective view of a lock clip in accordance with theembodiment of FIGS. 17A and 17B.

FIGS. 18A and 18B are cross-sectional views of a diaphragm-sealed valveaccording to a fourth preferred embodiment of the present invention.FIG. 18C is a perspective view of a hook in accordance with theembodiment of FIGS. 18A and 18B. FIG. 18D is a side view of the cylinderof FIGS. 18A and 18B. FIG. 18E is an enlarged view of a portion of FIG.18D

FIGS. 19A and 19B are cross-sectional views of a diaphragm-sealed valveaccording to a fifth preferred embodiment of the present invention.

FIGS. 20A and 20B are cross-sectional views of a diaphragm-sealed valveaccording to a sixth preferred embodiment of the present invention.FIGS. 20C and 20D are enlarged views of portions of FIGS. 20A and 20B,respectively.

FIGS. 21A and 21B are cross-sectional views of a diaphragm-sealed valveaccording to a seventh preferred embodiment of the present invention.FIG. 21C is an enlarged view of a portion of FIG. 21B.

While the invention will be described in conjunction with exampleembodiments, it will be understood that it is not intended to limit thescope of the invention to such embodiments. On the contrary, it isintended to cover all alternatives, modifications and equivalents as maybe included as defined by the present application.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the following description, similar features in the drawings have beengiven similar reference numerals. To preserve the clarity of thedrawings, some references numerals have been omitted, if they werealready identified in a preceding Figure.

Referring to FIGS. 2 and 4 to 6, there is shown a valve 30 according toa preferred embodiment of the present invention.

The valve 30 is of the diaphragm-sealed type valve. Such a valve may beused in analytical equipments of various types, and more particularlychromatographic equipments or online analyzers.

As illustrated in all of these Figures, the valve 30 includes four mainelements: a valve cap 32, a valve body 33, a diaphragm 36 compressiblypositioned between the valve cap 32 and the valve body 33, and a plungerassembly 38. The valve 30 may include a cylinder 34 and a bottom cap 40or other equivalent structure holding the plunger assembly 38 to thevalve body 33. In accordance with an aspect of the present invention,the valve 30 is also provided with a locking mechanism 119 which will bedescribed in conjunction with FIGS. 14A to 21C below.

Valve Cap

Still referring to FIGS. 2 and 4 to 6, and more clearly shown in FIGS.7A to 7E, the valve cap 32 has an interface, hereinafter referred to asthe first interface 42, and a plurality of process conduits 44 extendingthrough it. This first interface 42 is flat and smooth, and is incontact with the diaphragm 36 when the valve is assembled (as shown inFIGS. 4 to 6). Each process conduit 44, in this preferred embodimentamounting to six (6), ends in a process port 46 opening at the firstinterface 42. The process ports 46 are preferably circularly arranged onthe first interface 42. Best shown in FIG. 7C, each of the processconduits 44 are preferably formed by a larger threaded hole 48 forreceiving tubing connections and a smaller fluid passage 50 ending inthe process port 46. In this embodiment, the valve cap 32 has acylindrical shape and is for example made of electro-polished stainlesssteel. The valve cap 32 is also provided with screw holes 52 forreceiving socket head cap screws 54 (shown in FIG. 2), for holding thevalve cap 32 to the cylinder 34. The alignment of the valve cap 32 withthe cylinder 34 is ensured by dowel pins 56 (also shown in FIG. 2). Ofcourse, other arrangements for holding the valve cap 32 to the cylinder34 can be considered. Optionally, a layer of polymer covers the firstinterface 42 of the valve cap 32. Other materials, for example ceramicor various types of polymers, may be used as material for the valve cap32. Shapes other than a cylindrical one may also be considered. Ofcourse, other embodiments of the valve cap may include 4, 8, 10, 12 orany other convenient number of process ports.

Cylinder

Now referring to FIGS. 8A to 8G, there is shown a preferred embodimentof the cylinder 34 of the valve 30. Such as for the valve cap 32described above, the cylinder 34 also has an interface, hereinafterreferred to as the second interface 58, which faces the first interface42 of the valve cap when the valve is assembled (as shown in FIGS. 4 to6). Just as the first interface 42 of the valve cap 32, it is smooth andflat. The second interface 58 is provided with a main recess 60,preferably having a circular outline and it is aligned with the processports 46 of the valve cap 32 when the valve elements are assembled andthe valve is ready for use, as in FIGS. 4 to 6. The cylinder 34 alsoincludes a plurality of plunger passages 62 (more clearly shown in FIG.8F) each extending in the cylinder 34 and opening at one end in the mainrecess 60 between two of the process ports 46. The other ends of theplunger passages 62 open in a valve body cavity 63 which is for housingthe plunger assembly 38 (as shown in FIG. 2). The valve body is alsoprovided with a first set of screw holes 64 for receiving the sockethead cap screws 54 that hold the valve body to the valve cap (best shownin FIG. 8A) and a second set of screw holes 64 for receiving the sockethead cap screws 54 that hold the cylinder 34 to the bottom cap 40 (bestshown in FIG. 8D). Of course, other arrangements could be considered foraffixing the cylinder 34 to the bottom cap 40.

Diaphragm

Now referring to FIGS. 2, 4D and also to FIGS. 9A to 9C, there is showna preferred embodiment of the diaphragm 36 of the valve 30. Thediaphragm 36 has a first surface 74 facing the valve cap 32 and a secondsurface 76 facing the cylinder 34, the diaphragm 36 being compressiblypositioned between the first 42 and the second 58 interfaces when thevalve is assembled and ready for use (as in FIGS. 4 to 6). As moreclearly shown in FIG. 4D, the diaphragm has a pre-formed deformation 78lying within the main recess 60 of the cylinder 34, the first surface 74of the diaphragm 36 defining with the first interface 42 of the valvecap 32 a communication channel 80 between the process ports.

The diaphragm 36 can be made of multiple layers of polymer, with orwithout a thin metallic layer, or alternatively be made of metal only.Metals that may be used are stainless steel 316, aluminium,chrome-nickel alloy, copper and the like. For applications requiringhigh gas-tightness sealing, a diaphragm 36 made of multiple layers ofpolymer is preferably used, while other applications require a thinmetallic layer over the polymer layers.

Leaks Collection

With additional reference to FIG. 8B, the cylinder 34 may also beprovided with a leak collection system comprising a process purgingchannel 65 extending along the main recess 60, a process purging inletpassage 66 and process purging outlet passage 68. The process purginginlet passage 66 is connected to an entry 67 of a purge line, and theprocess purging outlet passage 68 is connected to an exit 69 of a purgeline. The cylinder 34 may further provided with a pair of fluid inlets70 and a pair of fluid outlets 72, the pair of fluid inlets 70 alsobeing connected to the entry 67 of a purge line, and the pair of fluidoutlets 72 being connected the exit 69 of the purge line. The cylinder34 may be provided with an actuation purging outlet passage 112. As seenin FIG. 7D, a purge circulation line may further be provided whichincludes inner and outer annular channels 51 and 53 extending at thefirst interface 42 of the valve cap 32. The fluid inlets 70 and thefluid outlets 72 each has a first opening 84 in the inner annularchannel 51 and a second opening 86 in the outer annular channel 53.

The operation of such a preferred leak collection system is described indetail in the present Applicant's above-mentioned applicationPCT/CA2008/002138 and will not, as such, be described further herein.

Plunger Assembly

Referring to FIGS. 2 and 6, 6A and 6B, there is shown a preferredembodiment of a plunger assembly 38 of the valve 30. In this preferredembodiment, the plunger assembly 38 (as indicated in FIG. 2) has aplurality of plungers 82, each placed in one of the plunger passages 62(more clearly shown in FIGS. 6A and 6B) of the cylinder 34. The term“plunger” is understood to mean a mechanism component driven by oragainst a mechanical force or fluid pressure. The plungers 82 can slidein the passages 62, between a closed position and an open position. Inthe closed position, the plunger 82 projects towards the first interface42, and presses the diaphragm 36 against the first interface 42 of thevalve cap 32, between two adjacent ports 46 for interruptingcommunication between these ports 46. In the open position, the plunger82 is retracted within the cylinder 34 and extends away from thediaphragm 36 for allowing communication between the two adjacent ports46. Preferably, each plunger 82 of the plunger assembly 38 is either anormally closed plunger 82 nc or a normally open plunger 82 no. Stillpreferably, guide sleeves 81 surround the normally open plungers 82 no,for facilitating the movement of the plungers into the passages. Theleft side plunger of FIG. 6 is shown in the closed position, whereas theright side plunger is shown in the open position. Of course, plungersmay take other shapes than that of a cylinder, as long as they can be inan open position where communication between the two adjacent ports 46is allowed, and a closed position where communication between the twoadjacent ports 46 is shut off. Other possible types of plungers 82 mayinclude for example bearing balls.

As shown in FIGS. 2, 5 and 6, the plunger assembly further includes afirst support structure 87 onto which the normally closed plungers 82 ncare mounted, and a second support structure 89 onto which the normallyopen plungers 82 no are mounted.

The valve 30 further comprises biasing means 94 for biasing the normallyclosed plungers 82 nc towards the diaphragm 36 and the normally openplunger 82 no away from the diaphragm 36. The valve body 33, the plungerassembly 38 and the locking mechanism 119 can be considered to form avalve body assembly.

An actuating mechanism 96 is further provided for actuating the valve30, as will be described in further detail herein below.

The support structures 87 and 89 are used in displacing the plungers 82within the passages 62. Preferably, the first support structure 87comprises a push plate 88 and a first piston 92 and the second supportstructure 89 comprises a second piston 90. As illustrated, the firstpiston 92 is located below the second piston 90 and for simplicity thesetwo pistons will hereinafter be referred to as the lower piston 92 andthe upper piston 90, respectively. Alternatively, it is also sometimesconvenient to refer to the first piston 92 as the normally closed piston92 since it supports the normally closed plungers 82 nc. Similarly, thesecond piston 90 may also be referred to as the normally open piston 90since it supports the normally open plungers 82 no.

The push plate 88 extends within the cavity 63 of the cylinder 34, inparallel to the second interface 58 of the cylinder 34, i.e.perpendicular to the plunger passages 62 and the central axis of thecylinder 34. The push plate 88 is movable transversally to the secondinterface 58, or in other words in parallel to the central axis of thecylinder 34. The normally closed plungers 82 nc are mounted on the pushplate 88. A guide sleeve 81 surrounds the push plate 88 for facilitatingits movement within the upper section of the cavity 63 of the cylinder34. A plurality of cavities 98 (shown in FIGS. 10A to 10C) extend acrossthe push plate 88 for allowing the normally open plungers 82 no to passthrough it. The upper piston 90 extends contiguously under the pushplate, the normally opened plungers 82 no being placed on it. The lowerpiston 92 extends under the upper piston 90 contiguously to it, thelower piston 92 being rigidly connected to the push plate 88, preferablywith a screw 54. O-rings 91 are preferably provided on the outline ofeach pistons, to properly seal the upper 92 and lower 90 pistons to theinner surface of the cylinder 34. In this preferred embodiment, wheneither the upper 90 or lower pistons 92 are retracted, theircorresponding plungers 82 attached thereto are pulled down, ensuringthat it does not press against the diaphragm 36. Thus, with thisparticular design, the valve 30 can advantageously be mounted in anyposition, since there are no “floating” plungers. FIGS. 11A and 11B showmore clearly the upper piston 90 of this preferred embodiment, whileFIGS. 12A and 12B show more clearly the lower piston 92.

More clearly shown in FIGS. 2 and 4, biasing means 94 ensure that thelower piston 92 is upwardly biased and that the upper piston 90 isdownwardly biased. Preferably, a Belleville washer 100 assemblycooperates with the lower piston 92 and a bottom cap screw 102 controlsan upward force on the Belleville washer assembly 100. Still preferably,it is a disc spring 104 extending over the upper piston 90 that exerts adownward force on the upper piston 90 and therefore downwardly biasesit.

Now referring to FIG. 5, to actuate the plungers, the actuatingmechanism 96 controls a distance or space between the upper 90 and lower92 pistons. In this preferred embodiment, it can be seen that theactuating mechanism 96 actuates the plungers 82 between the opened andclosed positions, by injection of actuation gas between the upper 90 andlower 92 pistons, the actuating mechanism being pneumatic actuators.

Referring to FIGS. 2, 5, 5A and 5B, in order to avoid situations wherean over pressurising of the actuator damages the diaphragm, the pistons90, 92 are may advantageously be provided with some room therearound toadd shims 108 of various thicknesses. These shims 108 stop the pistontravelling, since the piston will seat thereon. The idea is to use theright shim thickness for a particular application. These shims 108 areadvantageously used on the normally open piston 90 (or upper piston),more clearly shown in FIG. 5B, but also on the pushe plate 88 which isconnected to the normally closed piston 92, more clearly shown in FIG.5A. However, it is important to note that the use of such shims 108 onthe normally closed piston 92 is not intended to avoid damage when usinga higher operating pressure to actuate the valve 30, since pressure isused to lift the pistons to open the fluid communication channel betweentwo adjacent ports 46.

In fact, if the bottom cap set screw 102 is particularly adjusted inorder to require a high pressure to lift the corresponding piston 90,92, the result is that the time that all ports 46 are closed upon valveactuation will advantageously be longer, then eliminating even more therisk of cross port flow or the so called “mixing”. This higher pressureoperation will not cause damages since the corresponding piston strokeis limited by the shims stack. This provides a convenient way to adjustor to “time” the valve sequence operation by setting the step of “allports closed” more or less longer.

Now referring to FIGS. 2, 5, 13A and 13B, the bottom cap 40 is affixedto the cylinder 34, preferably with socket head cap screws 54, and italso houses the bottom cap set screw 102 that allow adjustment of thepressure exerted on the normally closed piston 92 via the Bellevillewasher assembly 100. The bottom cap 40 is also advantageously providedwith a bottom cap actuation vent 114 extending in it and locatedopposite to the actuating mechanism 96 of the plunger assembly 38, forpreventing pressure build up between the lower piston 92 and the bottomcap 40.

Locking Mechanism

The locking mechanism, which has been omitted from previous Figures forclarity, will now be described in detail in conjunction with FIGS. 14Ato 21C. Oftentimes, after diaphragm valves are built and fully tested,they are sealed in plastic packages, packed and stored in inventorybefore shipping to customers. Depending on various factors such asmarket demand, inventory management, customer need and the like, valvesare likely to stay unused for weeks or months after their manufacture.In addition, in some circumstances a valve owner may temporarily shutdown or remove a valve from active use for an undetermined amount oftime before putting it in service again. While a valve is idle, itsnormally closed plungers are in their closed position and thereforeapply a constant pressure on the diaphragm. Depending on diaphragmmaterial, this could lead to a permanent deformation of the diaphragm,and reduced efficiency of the valve. A pressure relief system istherefore advantageous provided to lock the normally closed in theiropen position when the valve is not in use.

A locking mechanism 119 in accordance with the present inventionadvantageously engages the first support structure 87 when the normallyclosed plungers 82 nc are in an open position, thereby acting againstthe biasing means 94 and physically preventing those plungers 82 nc fromreaching a closed position. As will be appreciated by one of ordinaryskill in the art, the use of such a locking mechanism 119 canadvantageously be used to prevent the normally closed plungers 82 ncfrom deforming, compressing or otherwise acting upon the diaphragm 36when the valve 30 is not in use.

It will also be appreciated that such locking mechanism 119 can alsoadvantageously ease replacement of the diaphragm during maintenance andthe like. By enabling a user to restrain the normally closed plungerswithin the valve body, it can be assured that those plungers do notinterfere with the proper positioning of the diaphragm.

FIGS. 14A to 15C illustrate a first embodiment of the locking mechanism119. The cylinder 34 includes at least one transverse passage 122extending therethrough from a side of the valve 30 to the lower piston92. The lower piston 92 also includes such a transverse passage 124,which is aligned with the transverse passage 122 of the cylinder 34 whenthe lower piston 92 is lowered, and the normally closed plungers 82 nctherefore is in the open position.

In FIGS. 14A to 14C, the normally closed plungers 82 nc are in theclosed position and the transverse passages 122 and 124 do not align. InFIGS. 15A to 15C however, the normally closed plungers 82 nc, as well asthe first support structure 87, have been retracted away from thediaphragm. A locking pin 120 then insertable through the alignedtransverse passages 122 and 124 of the cylinder 34 and lower piston 92.

In order to lock the valve, the actuating mechanism 96 is preferablyactivated: the lower piston 92 is forced downward by supplyingpressurized gas between the upper and lower pistons 90 and 92 asexplained above. This brings the transverse passages 122 and 124 of thecylinder 34 and lower piston 92 into alignment, and the locking pin 120can be inserted therein. Once the locking pin 120 is in place, theactuating mechanism 96 can be deactivated, and both the normally closed82 nc and to normally opened 82 no plungers will remain in their openposition, leaving the diaphragm 36 free of mechanical stress thereon.The valve 30 can simply be reactivated and the locking pin 120 removedwhenever the valve 30 needs to be used again. It will be appreciatedthat various other means for retracting the lower piston 92 and thenormally closed plungers 82 nc may similarly be used.

With reference to FIGS. 16A to 16C, a second preferred embodiment of thelocking mechanism 119 is illustrated. This second embodiment is similarto that illustrated in FIGS. 14A to 15C in that it provides at least onepin 121 which is adapted to be inserted first through a first transversepassage 122 in the valve body 33 and then though a second transversepassage 124 in the first support structure 87. Also like in FIGS. 14A to15C, the first transverse passage 122 is provided through the cylinder34 and the second transverse passage 124 is provided through the lowerpiston 92.

The embodiment of FIGS. 16A to 16C differs from that of FIGS. 14A to 15Cin that the locking pin 121 is provided with a flat extremity 130 havinga first thickness 132 and a second thickness 134, the latter beinggreater than the former. The second transverse passage 124 is providedwith a corresponding shape. The pin 121 is rotatable within the passages122 and 124 between a first orientation (seen in FIG. 16A) and a secondorientation (seen in FIG. 16B). In the first orientation, it is thesmaller, first thickness 132 which is oriented vertically, i.e. in linewith the plunger passages. Despite the presence of the pin 121 in bothpassages 122 and 124, the lower piston 92 remains free to travel betweenthe open and closed positions as the first thickness 132 does not fillthe second passage 124. In the second orientation however, the pin 121has been rotated 90° such that the second thickness 134 is orientedvertically. In this orientation, the larger second thickness 134 fillsthe second passage 124 vertically, thereby preventing the first pistonfrom moving with respect to the cylinder 34 and blocking the normallyclosed plungers 82 nc the open position.

By rotating the pin 121 from the first orientation to the second, itoperates as a cam, pushing the second piston 92 downwards. In thismanner, this second embodiment not only allows the user to manuallyrestrain the normally closed plungers 82 nc in the open position, butalso avoids the need to remove the pins 121 during use. It will beappreciated however that given a biasing means of sufficient strength,it could be inconvenient to manually actuate the locking mechanism 119.In such cases, the above-described method of activating the valve 30with the actuating mechanism 96 can similarly be used.

Preferably, and as illustrated in both the embodiments of FIGS. 14A to15C and 16A to 16C, two sets of transverse passages 122 and 124 andcorresponding locking pins 120, 121 are provided at opposite positionsaround the valve body 33. It will be understood however that any numberof passages 122 and 124 and pins 120 may be provided. Moreover, variousother shapes or types of passages 122 and 124 and pins 120, 121 couldsimilarly be used. In addition, it will be appreciated that thealignable passages 122 and 124 could be provided between other parts ofthe first support structure 87 and the valve body 33.

With reference to FIGS. 17A to 18E, third and fourth preferredembodiments of the locking mechanism 119 are illustrated. In both ofthese embodiments, the locking mechanism 119 comprises the combinationof at least one restraining mechanism 140 and at least one extension142. The extension 142 is mounted to the first support structure 87 andis movable therewith. The extension 142 extends through the valve body33. The restraining mechanism 140 is positionable between both the body33 and the extension 142 when the normally closed plungers 82 nc are inthe open position. In so doing, the restraining mechanism 140 engagesboth the valve body 33 and the extension 142 in order to prevent thelatter from moving with respect to the former.

With specific reference to the third embodiment illustrated in FIGS. 17Ato 17C, the extensions 142 extend downward from the lower piston 92,through the bottom cap 40. At the exposed end of the extension 142 is ashoulder 144 which faces the valve 30. In the illustrated embodiment,the extensions 142 are bolts and the shoulder 144 is the under-surfaceof the bolt head. In this embodiment, the restraining mechanism 140 is alocking clip which is able to be positioned between the shoulder 144 andthe bottom cap 40 when the normally closed plungers 82 nc are in theopen position, as seen in FIG. 17B. It will be appreciated that thelocking clip 140 could similarly be provided as pin which engages acorresponding hole through the end of the extension 142. Indeed, it willbe similarly appreciated that such an extension/locking clip combinationcould similarly be provided between other elements of the valve body 33and the first support structure 87.

With specific reference to the fourth embodiment illustrate in FIGS. 18Ato 18E, the extensions 142 extend outwards from the lower piston 92,through holes 146 in the sides of the cylinder 34. Preferably, the hole146 is provided with an elongated cross-section, as illustrated, so asto accommodate for the vertical travel of the extension 142. Therestraining mechanism 140 is embodied herein as a hook which is attachedto the base 40 and pivots about an axis 147 which is parallel to theextension 142. When the valve 30 is in use, the hook 140 may be pivotedaway from its respective extension 142. When the normally closedplungers 82 nc are in the open position, i.e. when the lower piston 92is at its lowermost, the hook 140 may be pivoted such that it engagesand restrains the extension 142.

Preferably, there are two sets of extensions 142 and hooks 140 providedat opposition positions around the valve 30, although it will beappreciated that more or less extensions 142 and hooks 140 couldsimilarly be used. It will also be appreciated that the extension 142could similarly extend from and through different parts of the firstsupport structure 87 and the valve body 33, respectively, and the hook140 could be mounted at a different part of the valve body 33.

With reference to FIGS. 19A to 21C, the fifth, sixth and seventhembodiments of the locking mechanism 119 are illustrated. In each ofthese three embodiments, the locking mechanism 119 comprises a threadedpassage 150 which extends downwards through the valve body 33, and alocking screw 152 which can be positioned at a locking position whichengages and blocks the first support structure 87 and the normallyclosed plungers 82 nc in the open position.

With specific reference to FIGS. 19A and 19B, one of the cap screws 54which fix the valve cap 32 to the cylinder 34, preferably the centralone, is replaced with the longer locking screw 152 which is able reach alocking position where it is engages the top of the push plate 88 whenthe latter is in open position. When the locking screw 152 is at thelocking position, as seen in FIG. 19B, the normally closed plungers 82nc are kept in the open position. Alternatively, a single locking 152screw may be provided in place of a regularly sized cap screw andlowered with respect to the plunger assembly 38 to the locking positionaccordingly.

With specific reference to FIGS. 20A to 20D, the central cap screw 54 isprovided with an internally threaded passage 150 which is able toreceive a smaller diameter locking screw 152. In order to restrain thenormally closed valves 82 nc in the open position, the locking screw 152is lowered to the locking position shown in FIGS. 20B and 20D wherein itengages the push plate 88 and thereby prevents the normally closedplungers 82 nc from returning to the closed position.

With specific reference to FIGS. 21A to 21C, the central cap screw 54 isprovided with a cap screw passage 156, which is unthreaded, throughwhich the locking screw 152 is able to pass. The threaded passage 150 isprovided within the push plate 88 (rather than through the cap screw 54itself), aligned below the unthreaded cap screw passage 156. Once again,the locking screw 152 may be lowered to the locking position shown inFIGS. 21B and 21C in order to restrain the push plate 88 and thenormally closed plungers 82 nc in the open position.

It will be appreciated by one of ordinary skill in the art that theabove mentioned advantages of a locking mechanism in accordance with thepresent invention could similarly be used with many other types ofdiaphragm-sealed valves, especially those including normally-closedvalves.

Although preferred embodiments of the present invention have beendescribed in detail herein and illustrated in the accompanying drawings,it is to be understood that the invention is not limited to theseprecise embodiments and that various changes and modifications may beeffected therein without departing from the scope of the presentinvention.

1. A valve comprising: a valve cap comprising a plurality of processconduits extending therethrough, each of the process conduits ending ina process port; a valve body facing the valve cap, the valve bodycomprising a plurality of plunger passages extending therein; adiaphragm positioned across the process ports and between the valve capand the valve body; a plunger assembly comprising: a plurality ofplungers, each of the plungers being positioned in a respective one ofthe plunger passages and slideable therein between a closed positionwherein the plunger deforms the diaphragm in order to blockcommunication between two of the process ports and an open positionwherein the plunger is retracted away from the diaphragm, each of theplungers being either a normally closed plunger or a normally openplunger; a first support structure upon which the normally closedplungers are mounted; and a second support structure upon which thenormally open plungers are mounted; a biasing mechanism for biasing thenormally closed plungers towards the diaphragm and biasing the normallyopen plungers away from the diaphragm; and a locking mechanism forengaging the first support structure and thereby physically restrain thenormally closed plungers in the open position.
 2. A valve according toclaim 1, wherein the locking mechanism comprises: a first transversepassage in the valve body which extends perpendicular to the plungerpassages, a second transverse passage extending through the firstsupport structure which is alignable with the first transverse passagewhen the normally closed plungers are in the open position; and alocking pin insertable through both the first and second transversepassages, thereby restraining the normally closed plungers in the openposition.
 3. A valve according to claim 2, wherein the locking pincomprises a flat extremity having first and second thicknesses, thefirst thickness being less than the second thickness, the locking pinrotatable within the first and second transverse passages between afirst orientation wherein the first thickness is aligned with theplunger passages and a second orientation wherein the second thicknessis aligned with the plunger passages.
 4. A valve according to claim 1,wherein the locking mechanism comprises: an extension mounted to thefirst support structure and which extends through the valve body, theextension being movable with the first support structure as the normallyclosed plungers slide between the open and closed positions; and arestraining mechanism positionable between the valve body and theextension when the normally closed plungers are in the open position. 5.A valve according to claim 4, wherein the extension extends parallel tothe plunger and ends with a shoulder, and wherein the restrainingmechanism is a lock clip adapted to be inserted between the shoulder andthe valve body when the normally closed plungers are in the openposition.
 6. A valve according to claim 4, wherein the extension extendsperpendicular to the plunger passages, and wherein the restrainingmechanism is a hook which is pivotable about the valve body and adaptedto restrain the extension when the normally closed plungers are in theopen position.
 7. A valve according to claim 1, wherein the lockingmechanism comprises: a threaded passage extending through the valve bodyparallel to the plunger passages; and a locking screw adapted tothreadedly engage the threaded passage and be positioned at a lockingposition wherein the locking screw engages the first support structurethereby restraining the normally closed plungers in the open position.8. A valve according to claim 7, wherein the valve body comprises aplurality of cap screws for fixing the valve cap thereto, the lockingscrew being one of the plurality of cap screws.
 9. A valve according toclaim 7, wherein the valve body comprises a plurality of cap screws forfixing the valve cap thereto, the threaded passage extending through oneof the plurality of cap screws.
 10. A valve according to claim 7,wherein the valve body comprises a plurality of cap screws for fixingthe valve cap thereto, one of the plurality of cap screws being providedwith a cap screw passage aligned with the threaded passage, the lockingscrew being adapted to pass through the cap screw passage in order toengage the threaded passage.
 11. A valve according to claim 1, whereinthe first support structure comprises a push plate extending within thevalve body and movable therewithin, the normally closed plunger beingmounted on the push plate.
 12. A valve according to claim 11, whereinthe first support structure further comprises a first piston extendingwithin the valve body parallel to the push plate and connected rigidlythereto, the locking mechanism engaging one of the push plate and thefirst piston.
 13. A valve according to claim 12, wherein the secondsupport structure comprises a second piston extending within the valvebody and movable therewithin between the push plate and the firstpiston, the normally open plungers being mounted on the second piston;the push plate comprising a plurality of cavities extending thereacrossfor allowing passage of the normally open plungers.
 14. A valveaccording to claim 13, further comprising an actuating mechanism foractuating the normally closed and normally open plungers between theopened and closed positions thereof, the actuating mechanism controllinga distance between the first and second pistons.
 15. A valve accordingto claim 1, wherein the valve body comprises a cylinder in which thefirst and second support structures are translatable and a bottom capaffixed to the cylinder opposite the valve cap.
 16. A valve bodyassembly for a valve comprising a valve cap, the valve cap comprising aplurality of process conduits extending therethrough, each of theprocess conduits ending in a process port, the valve further comprisinga diaphragm positioned across the process ports, the valve body assemblycomprising: a valve body comprising a plurality of plunger passagesextending therein, the diaphragm being positioned between the valve bodyand the valve cap; a plunger assembly comprising: a plurality ofplungers, each of the plungers being positioned in a respective one ofthe plunger passages and slideable therein between a closed positionwherein the plunger is adapted to deform the diaphragm in order to blockcommunication between two of the process ports, and an open positionwherein the plunger is retracted away from the diaphragm, each of theplungers being either a normally closed plunger or a normally openplunger; a first support structure upon which the normally closedplungers are mounted; and a second support structure upon which thenormally open plungers are mounted; a biasing mechanism for biasing thenormally closed plungers towards the diaphragm and biasing the normallyopen plungers away from the diaphragm; and a locking mechanism forengaging the first support structure and thereby physically restrain thenormally closed plungers in the open position.
 17. A valve body assemblyaccording to claim 16, wherein the locking mechanism comprises: a firsttransverse passage in the valve body which extends perpendicular to theplunger passages, a second transverse passage extending through thefirst support structure which is alignable with the first transversepassage when the normally closed plungers are in the open position; anda locking pin insertable through both the first and second transversepassages, thereby restraining the normally closed plungers in the openposition.
 18. A valve body assembly according to claim 16, wherein thelocking mechanism comprises: an extension mounted to the first supportstructure and which extends through the valve body, the extension beingmovable with the first support structure as the normally closed plungersslide between the open and closed positions; and a restraining mechanismpositionable between the valve body and the extension when the normallyclosed plungers are in the open position.
 19. A valve body assemblyaccording to claim 16, wherein the locking mechanism comprises: athreaded passage extending through the valve body parallel to theplunger passages; and a locking screw adapted to threadedly engage thethreaded passage and be positioned at a locking position wherein thelocking screw engages the first support structure thereby restrainingthe normally closed plungers in the open position.